Discover Phnom Kulen · Landscapes & Biodiversity
What Phnom Kulen Is Made Of
Explore the nature and wildlife of this ancient evergreen forest.
Protected park area
Highest point
Watershed fed by Kulen
Recorded plant species
fauna species with global or national conservation concerns
Six things to know
Phnom Kulen isn’t just a backdrop to the temples of Angkor:
its stone, water and forest made the empire possible.
Open any topic below to explore it at your own pace.
FOUNDATIONS
A sandstone massif,
100 million years old
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Phnom Kulen is the name given to the main mountain range of the Angkor–Siem Reap region: a plateau stretching 26 by 15 kilometers at its widest, running northwest to southeast. A second, narrower range continues 20 kilometers further northwest along the same line, home to the river bed carvings of Kbal Spean. Between the two, the isolated hills of Phnom Hop and Phnom Dei rise near the 9th-century temple of Banteay Srei.
The entire massif is sandstone laid down between roughly 200 and 100 million years ago, in the Upper Jurassic and Early Cretaceous periods. Sheer cliffs separate the plateau from the lowlands, while the interior holds a rougher terrain of smaller cliffs, streams and valleys, more rugged in the north. The highest point, Phnom Thbeng, stands near Ta Penh village at 496 m. The initial 37,373-hectare national park followed this natural cliff line around the southeastern plateau and roughly half of the northwestern range. It was extended in 2023 to a northern corridor and to the northwest Chankran Roy Community Protected area. To the southeast of the massif, a large area was used as a quarry to extract sandstone blocks used to build the Angkor temples.
The entire massif is sandstone laid down between roughly 200 and 100 million years ago, in the Upper Jurassic and Early Cretaceous periods. Sheer cliffs separate the plateau from the lowlands, while the interior holds a rougher terrain of smaller cliffs, streams and valleys, more rugged in the north. The highest point, Phnom Thbeng, stands near Ta Penh village at 496 m. The initial 37,373-hectare national park followed this natural cliff line around the southeastern plateau and roughly half of the northwestern range. It was extended in 2023 to a northern corridor and to the northwest Chankran Roy Community Protected area. To the southeast of the massif, a large area was used as a quarry to extract sandstone blocks used to build the Angkor temples.
LANDSCAPE
Cliffs, slabs and sacred rock shelters
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The cliffs ringing the plateau open onto sweeping views across the Angkorian plain, toward Phnom Bok and Phnom Bakheng, the western range and Kbal Spean, and the distant mountains of Kompong Thom,Preah Vihear and Dangrek to the northern border of Cambodia. Within the plateau, viewpoints such as Prasat Krohom and Poeng Tbal look out over the forest below.
Large sandstone boulders and exposed rock slabs define Kulen’s terrain. Natural shelters eroded/formed among these boulders drew Angkorian-era hermits, and some remain active places of worship, most notably Preah Ang Thom, the most actual sacred site on the mountain. Where vegetation grows directly on bare rock, the landscape opens into savanna-like clearings known locally as veal, the largest and most representative being Veal Preah Kral, Veal Khla Angkuy, Veal Prasat Krohom and Veal Changkran Roy.
Large sandstone boulders and exposed rock slabs define Kulen’s terrain. Natural shelters eroded/formed among these boulders drew Angkorian-era hermits, and some remain active places of worship, most notably Preah Ang Thom, the most actual sacred site on the mountain. Where vegetation grows directly on bare rock, the landscape opens into savanna-like clearings known locally as veal, the largest and most representative being Veal Preah Kral, Veal Khla Angkuy, Veal Prasat Krohom and Veal Changkran Roy.
HYDROLOGY
The source of an entire watershed
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Phnom Kulen is the headwater of the whole Siem Reap–Angkor watershed. The Siem Reap River rises here from four main tributaries before dropping, after its principal waterfall, into a steeper course toward the plain, merging with the O’Russei stream before irrigating the Angkor temples, moats, Siem Reap town, and finally the Tonle Sap Lake.
Two further rivers also begin on Kulen: the Puok River to the west and the Roluos River to the east, gathering streams from the southwestern slopes before passing Chau Srey Vibol temple. A fourth, the O’Samrong, drains the eastern side toward Damdek and the floating village of Kompong Pluk. Together with the Tonle Sap, these rivers define a watershed of over 3,600 km² touching some 470 villages.
This role is spiritual as well as hydraulic: water flowing from Kulen, sanctifying the carved lingas of the Kbal Spean riverbed and the thousand-linga site, is considered holy throughout Cambodia, and has been used in royal coronation ceremonies.
Two further rivers also begin on Kulen: the Puok River to the west and the Roluos River to the east, gathering streams from the southwestern slopes before passing Chau Srey Vibol temple. A fourth, the O’Samrong, drains the eastern side toward Damdek and the floating village of Kompong Pluk. Together with the Tonle Sap, these rivers define a watershed of over 3,600 km² touching some 470 villages.
This role is spiritual as well as hydraulic: water flowing from Kulen, sanctifying the carved lingas of the Kbal Spean riverbed and the thousand-linga site, is considered holy throughout Cambodia, and has been used in royal coronation ceremonies.
WILDLIFE
27 species at risk
BIRDS
A third of Cambodia’s birds species
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A 2013 biodiversity assessment recorded 198 bird species on Phnom Kulen. A more recent naturalistic assessment of the park’s biodiversity and conservation prospects, led by Vincent Romera (Humy) with Jean-Baptiste Chevance of the Archaeology and Development Foundation (ADF) and Tony Yon, completed in October 2023 and reviewed in November 2025, put that number into national perspective: Phnom Kulen alone is home to roughly a third of all bird species recorded in Cambodia, with 210 species observed, including the Malayan Night-Heron filmed by the camera traps.
MAMMALS & PRIMATES
Rare primates and a shrinking web of forest mammals
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The 2013 assessment recorded 25 mammal species on Kulen, ten of them of international conservation concern: the black giant squirrel, Long-tailed Macaque , Bengal slow loris, northern pig-tailed macaque, pileated gibbon, Indochinese silver langur, binturong and hog-badger. The 2023 assessment confirms Kulen as a refuge for rare or globally threatened primates, including the pileated gibbon, the Bengal slow loris and the long-tailed macaque. Local accounts also describe historical sightings of elephants, tigers and bears on the mountain, though deforestation and hunting have sharply reduced wildlife in recent decades.
BATS
Nearly 40% of Cambodia’s bat species (27)
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Phnom Kulen holds 27 recorded bat species, representing close to 40 percent of all bat species known in Cambodia, one of the clearest signs of how concentrated the park’s biodiversity is for its size.
REPTILES & AMPHIBIANS
Cambodia’s top park for snakes, and a stronghold for threatened turtles
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The 2013 assessment recorded 25 mammal species on Kulen, ten of them of international conservation concern: the black giant squirrel, Long-tailed Macaque , Bengal slow loris, northern pig-tailed macaque, pileated gibbon, Indochinese silver langur, binturong and hog-badger. The 2023 assessment confirms Kulen as a refuge for rare or globally threatened primates, including the pileated gibbon, the Bengal slow loris and the long-tailed macaque. Local accounts also describe historical sightings of elephants, tigers and bears on the mountain, though deforestation and hunting have sharply reduced wildlife in recent decades.
INVERTEBRATES
Butterflies, dragonflies and over 430 species of moth
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The 2023 assessment found that Phnom Kulen holds more than a third of all butterfly species recorded in Cambodia, and almost half of the country’s known dragonflies and damselflies. More than 430 moth species and taxa have been identified on the mountain to date.
This section will continue to expand as more species-level detail from the 2023–2025 assessment becomes available
FOREST & FLORA
One of the last refuge of evergreen forest
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Declared a national park in 1993, Phnom Kulen remains the only inhabited highland within its own boundaries, placing direct pressure on its evergreen and semi-evergreen forest. In the late 1960s, land cleared for slash-and-burn agriculture covered around 75 km²; by 2017, surveys estimated only 20 to 23 percent of the park remained forested, mainly lost to the spread of cashew cultivation.
What remains is rich: 775 wild plant species recorded, including ten of Cambodia’s forty IUCN-listed threatened plant species. The lychee tree that gave the mountain its name, Phnom Kulen, “Mountain of Lychees”, is itself now under threat. Local communities still depend on the forest for medicinal plants, especially black ginger, along with resin, rattan, bamboo and wild fruit.
What remains is rich: 775 wild plant species recorded, including ten of Cambodia’s forty IUCN-listed threatened plant species. The lychee tree that gave the mountain its name, Phnom Kulen, “Mountain of Lychees”, is itself now under threat. Local communities still depend on the forest for medicinal plants, especially black ginger, along with resin, rattan, bamboo and wild fruit.
CONSERVATION
Replanting, patrols, and a path for local families
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The Ministry of Environment (MoE), together with Community Protected Area members and partners including ADF, AGRISUD International, UNDP and UNEP, works to slow deforestation through zoning, ranger patrols and reforestation. With more than 200 hectares replanted since 2015, and four nurseries running at four primary schools on the plateau, ADF initiated this dynamic, in close collaboration with the Ministry.The MoE has now a regional tree nursery at the entrance of the Park.
Alongside enforcement and with the support of ADF and AGRISUD International, alternative livelihood programs now support more than 360 local families in growing fruit trees,black ginger and pepper, or raising poultry and pigs, a path that eases pressure on the forest while sustaining the communities who call Kulen home.
Alongside enforcement and with the support of ADF and AGRISUD International, alternative livelihood programs now support more than 360 local families in growing fruit trees,black ginger and pepper, or raising poultry and pigs, a path that eases pressure on the forest while sustaining the communities who call Kulen home.